A fourth person with severely impaired vision also experienced gains in their sight, but they did not last.

Bharti says it isn’t clear what exactly caused the vision improvements. It’s possible that the transplanted cells themselves proliferated in the recipient’s corneas. But the vision gains could also be due to the removal of scar tissue before the transplant, or the transplant triggering the recipient’s own cells to migrate from other regions of the eye and rejuvenate the cornea.

These parts are a little concerning to me, but I’m still hopeful.